Ultrasonic imaging systems of the transmission type wherein a transmitting transducer and a receiving transducer are located at opposite sides of an object or specimen under examination are well known as shown, for example, in U.S. Pat. No. 3,937,066, Green et al and 4,457,175, Ramsey, Jr. et al. Generally C-scan images are provided by transmission type systems which lie in a plane normal to the transmitted waves. Echo type ultrasonic imaging systems also are well known as shown, for example, in U.S. Pat. Nos. 4,016,750, P. S. Green and 4,305,296, Green et al. Generally B-scan type images are produced by echo type systems wherein the image formed lies in a plane containing the propagated waves. Of course, C-scan images also may be obtained using echno techniques.